LED with Integrated Substrate Junction for Breakdown Voltage
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Solution Overview
Problem
Existing light-emitting diodes (LEDs) face challenges in achieving high breakdown voltage properties without increasing size and cost, as well as efficiently managing reverse overcurrents, particularly due to the need for additional electronic components like protective diodes which complicate manufacturing and increase costs.
Innovation Solution
A light-emitting diode design featuring a second pn junction structure integrated into the silicon single crystal substrate, combined with a light-reflecting hole and metallic films for efficient light reflection and current distribution, allowing for improved breakdown voltage without external protective diodes, thereby reducing size and cost while enhancing light-emitting intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external protective diodes are added to improve breakdown voltage, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the protective diode function with the LED structure by forming a second pn junction directly in the silicon substrate beneath the light-emitting section. This integration eliminates the need for separate external protective diodes and their associated wiring, thereby improving breakdown voltage while reducing device complexity
Solution Approach 2:
The silicon substrate serves multiple functions: it acts as the base substrate for the LED structure, provides the second pn junction for overcurrent protection, and enables both light emission and protective functions within a single component, reducing the need for additional parts
2Reliability
If external protective diodes are added to improve breakdown voltage, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The protective function is merged into the LED manufacturing process itself by forming the second pn junction during substrate preparation, eliminating the need for separate protective diode components and their assembly, thereby reducing manufacturing cost
Solution Approach 2:
The LED structure provides its own protective function through the integrated second pn junction that automatically clamps reverse overvoltage, eliminating the need for external protective components and reducing manufacturing steps
3Reliability
If protective diodes are provided separately to improve breakdown voltage, then reliability is improved, but chip size increases
Solution Approach 1:
The protective diode function is merged into the substrate area beneath the light-emitting section, utilizing the same chip real estate for both light emission and protection functions, thereby preventing chip size increase
Solution Approach 2:
The second pn junction is formed in the vertical dimension of the silicon substrate beneath the light-emitting section, utilizing the substrate thickness rather than lateral space, which allows protection function without increasing chip footprint
4Reliability
If multiple electronic parts are incorporated to improve breakdown voltage, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
Multiple functions (light emission, overcurrent protection, voltage clamping) are merged into a single integrated structure with the second pn junction formed in the substrate, eliminating the need for separate electronic parts and simplifying manufacturing
Solution Approach 2:
The LED structure provides its own protective functions through the integrated second pn junction that automatically activates during reverse overvoltage conditions, eliminating the need for external protective components and their assembly
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively manages reverse overcurrents, maintains high breakdown voltage, and improves light-emitting intensity by integrating the second pn junction structure and metallic films within the LED, reducing the need for external components and simplifying manufacturing.
Implementation Method 1
a light-reflecting hole is provided in the silicon single crystal substrate from the back surface of the substrate opposite to the side on which the light-emitting section of the silicon single crystal substrate is provided toward the stacking direction, and the inner surface of the light-reflecting hole and the back surface of the silicon single crystal substrate are coated with a metallic film
Implementation Method 2
a second pn junction structure is constructed in a region which extends from the first conductive type silicon single crystal substrate to the light-emitting section
Data Source
AI summary
The present invention provides a light-emitting diode (10) including a first conductive type silicon single crystal substrate (101), a light-emitting section (40) including a first pn junction structure composed of a III-group nitride semiconductor on the substrate, a first polarity ohmic electrode (107b) provided on the light-emitting section, and a second polarity ohmic electrode (108) on the same side as the light-emitting section with respect to the substrate, wherein a second pn junction structure (30) is configured in a region which extends from the substrate to the light-emitting section, the substrate is provided with a light-reflecting hole (109) from the back surface of the substrate opposite to the side on which the light-emitting section of the substrate is provided toward the stacking direction, and the inner surface of the light-reflecting hole and the back surface of the substrate are coated with a metallic film (110).